The present invention relates to a sensor, and in particular preferably to a low power pressure sensor with Bluetooth capability.
Pressure sensors are used for measuring the pressure of fluid (e.g., gas or liquid) often within a pipe, such as a duct. Referring to FIG. 1, in one implementation a pressure sensor is installed in a housing in a panel and a flexible tubular connector is extended into a duct. The pressure as sensed through the flexible tubular connector is measured by a sensor included within the housing to determine a static pressure. Referring to FIG. 2, in another implementation a pressure sensor is installed in a housing in a panel and a pair of flexible tubular connectors is extended into a duct. The pressure as sensed through the pair of flexible tubular connectors is measured by a sensor included within the housing to determine a static and/or differential pressure. Referring to FIG. 3, in another implementation a pressure sensor may be installed on the exterior surface of a duct and through a sensor member extending into the duct the static pressure is sensed through the sensor member by a sensor included within the housing. Referring to FIG. 4, in another implementation a pressure sensor may be installed on the exterior surface of a duct and through a sensor member extending into the duct, the static and/or differential pressure as sensed through a pair of tubular connectors is sensed through the sensor member by a sensor included within the housing.
Referring to FIG. 5, the pressure sensor may include a display attached to the housing for displaying the current pressure and/or differential pressure being sensed. In many cases, a 4-20 ma loop circuit is used to provide power to the pressure sensor for its electronics included therein, and to provide an analog output signal indicating the pressure levels to a remote sensing device. The pressure sensor may also include a digital input and a digital output, if desired. For example, a 4 ma output signal may indicate a relatively low pressure while a 20 ma output signal may indicate a relatively high pressure.
Referring to FIG. 6, the pressure sensor may include a transmitter/receiver that provides the 4-20 ma analog output signal to a process monitor/controller which receives the 4-20 ma output signal. Similarly, the process monitor/controller may include a transmitter/receiver that provides the 4-20 ma analog output signal to the pressure sensor which receives the 4-20 ma output signal.
Referring also to FIG. 7, the power provided to the pressure sensor using the 4-20 ma loop circuit may be used to provide suitable power for the sensor electronics included within the pressure sensor. The sensor electronics may include, for example, a microcontroller, a display controller module, a display module, a sensor, a power management module, a signal processing module, and a transmitter/receiver module to provide a suitable 4-20 ma analog output signal. As it may be observed, with relatively low voltage levels used for the 4-20 ma loop signal there is limited power available for additional electronics within the pressure sensor, while maintaining the ability to provide a suitable 4-20 ma output signal to the process monitor/controller.
What is desired, therefore, is a pressure sensor that includes additional electronics therein, while still maintaining the use of a 4-20 ma loop signal as the power source.
The foregoing and other objectives, features, and advantages of the invention may be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings.